/Engine/Plugins/NetcodeUnitTest/NetcodeUnitTest/Source/NetcodeUnitTest/Classes/Net/UnitTestPackageMap.h
This is the meat of the PackageMap class which serializes a reference to Object.
virtual bool SerializeObject ( [FArchive](API\Runtime\Core\Serialization\FArchive) & Ar, [UClass](API\Runtime\CoreUObject\UObject\UClass) * InClass, [UObject](API\Runtime\CoreUObject\UObject\UObject) *& Obj, [FNetworkGUID](API\Runtime\Core\Misc\FNetworkGUID) * OutNetGUID )